Computer Engineering Commons^™

On-Line Scheduling With Hard Deadlines, Sally A. Goldman, Jyoti Parwatikar, Subhash Suri

All Computer Science and Engineering Research

We study non-preemptive, online admission control in the hard deadline model: each job must be either serviced prior to its deadline, or be rejected. Our setting consists of a single resource that services an online sequence of jobs; each job has a length indicating the length of time for which it needs the resource, and a delay indicating the maximum time it can wait for the service to be started. The goal is to maximize total resource utilization. The jobs are non-preemptive and exclusive, meaning once a job begins, it runs to completion, and at most one job can use …

Learning From Examples With Unspecified Attribute Values, Sally A. Goldman, Stephen S. Kwek, Stephen D. Scott

All Computer Science and Engineering Research

We introduce the UAV learning model in which some of the attributes in the examples are unspecified. In our model, an example x is classified positive (resp., negative) if all possible assignments for the unspecified attributes result in a positive (resp., negative) classification. Otherwise the classificatoin given to x is "?" (for unknown). Given an example x in which some attributes are unspecified, the oracle UAV-MQ responds with the classification of x. Given a hypothesis h, the oracle UAV-EQ returns an example x (that could have unspecified attributes) for which h(x) is incorrect. We show that any class learnable in …

Diagnostic Screening Of Digital Mammograms Using Wavelets And Neural Networks To Extract Structure, Barry L. Kalman, Stan C. Kwasny, William R. Reinus

All Computer Science and Engineering Research

As the primary tool for detecting breast carcinoma, mammography provides visual images from which a trained radiologist can identify suspicious areas that suggest the presence of cancer. We describe an approach to image processing that reduces an image to a small number of values based on its structural characteristics using wavelets and neural networks. To illustrate its utility, we apply this methodology to the automatic screening of mammograms for mass lesions. Our results approach performance levels of trained human mammographers.

Routing Table Compression Using Binary Tree Collapse, Jonathan Turner, Qiyong Bian, Marcel Waldvogel

All Computer Science and Engineering Research

This paper describes an algorithm which can roughly halve the size of the current Internet routing tables. This algorithm is based on the radix trie representation of routing tables, which was firstly used in the BSD Unix distributions. The binary tree representation, which is a simplified case of radix tree, does well at showing the relationships among all routing table entries and provides us a way to build a collapse algorithm based on its internal structure. The binary tree collapse algorithm consists of three techniques, with the first two quite intuitive while the third is a bit more elaborate. All …

Master Of Science Degree Programs 1998, Nova Southeastern University

College of Engineering and Computing Course Catalogs

No abstract provided.

Router Plugins: A Modular And Extensible Software Framework For Modern High Performance Integrated Services Routers, Dan Decasper, Zubin Dittia, Guru Parulkar, Bernhard Plattner

All Computer Science and Engineering Research

Present day routers typically employ monolithic operating systems which are not easily upgraded and extensible. WIth the rapid rate of protocol development it is becoming increasingly important to dynamically upgrade router software in an incremental fashion. We have designed and implemented a high performance, modular, extended integrated services router software architecture in the NetBSD operating system kernel. This architecture allows code modules, called plugins, to be dynamically added and configured at run time. One of the novel features of our design is the ability to bind different plugins to individual flows; this allows for distinct plugin implementations to seamlessly coexist …

Terabit Burst Switching Progress Report (12/97-2/98), Jonathan S. Turner

All Computer Science and Engineering Research

This report summarizes progress on the Terabit Burst Switching Project at Washington University for the period from December 15, 1997 through March 15, 1998. Efforts during this period have concentrated on working out details of the burst switch architecture, evaluating a variety of implementation alternatives and developing the physical design of the 160 Gb/s ATM switch to allow demonstration of the burst switch within a realistic network context.

Integrating A Constraint Mechanism With The Javabeans Model, William M. Shapiro

All Computer Science and Engineering Research

The JavaBeans component model allows users to plug together software components to create Java applications by specifying simple relationships between component events and properties. This paper describes work on augmenting the simple JavaBeans model with a multi-way constraint mechanism that allows users to graphically specify more complex multi-way contraints, resolve cyclical constraints between bean properties and graphically layout bean components. We also discuss weaknesses in the JavaBeans model and Java Abstract Windowing Toolkit (AWT) that were discovered while integrating a constraint mechanism with JavaBeans.

Lime: Linda Meets Mobility, Gian Pietro Picco, Amy L. Murphy, Gruia-Catalin Roman

All Computer Science and Engineering Research

LIME is a system designed to assist in the rapid development of dependable mobile applications over both wired and ad hoc networks. Mobile agents reside on mobile hosts and all communication takes place via transiently shared tuple spaces distributed across the mobile hosts. The decoupled style of computing characterizing the Linda model is extended to the mobile environment. At the application level, both agents and hosts perceive movement as a sudden change of context. The set of tuples accessible by a particular agent residing on a given host is altered transparently in response to changes in the connectivity pattern among …

Tcp Dynamic Acknowledgment Delay: Theory And Practice, Daniel R. Dooly, Sally A. Goldman, Stephen D. Scott

All Computer Science and Engineering Research

We study an on-line problem that is motivated by the networking problem of dynamically adjusting delays of acknowledgments in the Transmission Control Protocol (TCP). The theoretical problem we study is the following. There is a sequence of n packet arrival times A = and a look-ahead coefficient L. The goal is to partition A into k subsequences sigma1, sigma2, ...,sigmak (where a subsequence end is defined by an acknowledgment) that minimizes a linear combination of the cost for the number of acknowledgments sent and the cost for the additional latency introduced by delaying acknowledgments. At each arrival, an oracle provides …

The Playground Mediator: Visual Tool For Configuring And Debugging Distributed Applications, T. Paul Mccartney

All Computer Science and Engineering Research

The Mediator is a visual configuration tool for use with The Programmers' Playground distributed programming environment. With the Mediator, one can interactively launch distributed application modules, configured communication among the modules, observe communication patterns, interactively control module communication, kill running modules, and receive imported applications from a separate World Wide Web interface. This manual describes how to use the Mediator both as a stand-alone configuration tool and as a visual interface to the Playground Application Management System.

Integrating Security Into The Curriculum, Cynthia E. Irvine, Shiu-Kai Chin, Deborah Frincke

Electrical Engineering and Computer Science - All Scholarship

The number of skilled practitioners of computer security who are able to address the complexities of modern technology and are familiar with successful approaches to system security is very small. People want security but are faced with two difficulties. First, they do not know how to achieve it in the context of their enterprises. They may not even know of a way to translate organizational procedures into policies, much less implement a set of mechanisms to enforce those policies. Second, they have no way of knowing whether their chosen mechanisms are effective. The recent US Presidential Commission on Critical Infrastructure …

Building A Secure Intranet, Fred J. Berryman

Theses

This thesis will explain the vulnerabilities of computers in a networking environment and demonstrate proper procedures for building a secure Intranet.

The Internet is built around the concept of open communication. Data is shared around the globe just as easily as it is from one office or cubical to the next. Corporations are skeptical about putting company data on such a public transport mechanism as the Internet, but the tools used on the Internet are exciting and everyone wants to use them. Out of a desire for the best of both worlds, the Intranet was born.

An intranet that has …

Cognitive Agents, Michael N. Huhns, Munindar P. Singh

Faculty Publications

Several researchers have proposed using cognitive concepts as a semantic basis for agent communications (M.N. Huhns and M.P. Singh, 1997). One of the leading candidates for such a semantics is based on Arcol, the communication language used within Artimis. Interestingly, this application (not only of Arcol, but also in general) appears extremely misguided. The intentional concepts are well suited to designing agents, but are not suited to giving a basis to a public, standardizable view of communication. A challenge for using the cognitive concepts is that although they are natural in several respects and can guide implementations, full blown implementations …

Personal Assistants, Michael N. Huhns, Munindar P. Singh

Faculty Publications

Already there are simple personal agents to help with some of our shopping. There are agents to track stocks in our portfolios, advise us on how to use particular software products, and arrange meetings within corporate workgroups. However, none of these agents takes more than one aspect of our activities into account, nor do they adapt easily to our preferences. Personal assistants, on the other hand, are agents that can represent individuals on the Web. They help users in their day-to-day activities, especially those involving information retrieval, negotiation, or coordination. A personal assistant might schedule a meeting and then, based …

Workflow Agents, Michael N. Huhns, Munindar P. Singh

Faculty Publications

Software agents as user agents, resource agents, and brokers may be able to enhance usefulness of workflow applications. Workflow technology is important to network computing because workflows exist naturally wherever distributed resources are interrelated. The problem with current workflow technology is that it is often too rigid. The lack of freedom accorded to human participants causes workflow management systems to appear unfriendly. As a result, they are often ignored or circumvented. This rigidity also causes productivity losses by making it harder to accommodate the flexible, ad hoc reasoning of human intelligence. Another challenge is that system requirements are rarely static. …

All Agents Are Not Created Equal, Michael N. Huhns, Munindar P. Singh

Faculty Publications

As the technology advances, we can expect the development of specialized agents to be used as standardized building blocks for information systems. Two trends lend credence to such a prediction. First, software systems in general are being constructed with larger components, such as ActiveX and JavaBeans, which are becoming closer to being agents themselves. They have more functionality than simple objects, respond to events autonomously, and, most importantly, respond to system builders at development time, as well as to events at runtime. Moreover, there is a move toward more cooperative information systems, in which the architecture itself plays an important …

Anthropoid Agents, Michael N. Huhns, Munindar P. Singh

Faculty Publications

In the study of agents on the Internet, we often ascribe to them human qualities, such as beliefs and intentions. These qualities are best understood as metaphors that give developers a way to talk about and design the capabilities and applications of agents. Despite all the progress in computing, users have been slow to accept the technology. They have often accepted what was thrown at them, but only under economic duress. Bringing the technology closer to their emotional needs might ease this resistance. So how can we put a human face on computing? Maybe by putting an animated face on …

A Corba-Base Integration Of Distributed Electronic Healthcare Records Using The Synapses Approach, Jane Grimson, William Grimson, Damon Berry, Gaye Stephens, Eoghan Felton, Dipak Kalra, Pieter Toussaint, Onno Weir

Articles

The ability to exchange in a meaningful, secure, and simple fashion relevant healthcare data about patients is seen as vital in the context of efficient and cost-effective shared or team-based care. The electronic healthcare record (EHCR) lies at the heart of this information exchange, and it follows that there is an urgent need to address the ability to share EHCR's or parts of records between carers and across distributed health information systems. This paper presents the Synapses approach to sharing based on a standardized shared record, the Federated Healthcare Record, which is implemented in an open and flexible manner using …

Usable Software And It's Attributes: A Synthesis Of Software Quality: European Community Law And Human-Computer Interaction., Ronan Fitzpatrick, Catherine Higgins

Conference papers

Strategic managers and IS professionals who are responsible for specifying, acquiring and producing quality software products are not supported by the endless flow of new international standards, legislation and user requirements. In order to clarify the current situation for everybody concerned with software quality, and especially those interested in usability, there is a need for a new review and evaluation of the various strands that contribute to software quality. By way of review this paper recalls the original software quality factors which were defined twenty years ago by McCall et al. and presents a methodical analysis and synthesis of three …

Electromagnetic Beam Directing Means-Sample Analysis System Stage, And Method Of Use, Daniel W. Thomspon, Darin W. Glenn, John A. Woollam

Department of Electrical and Computer Engineering: Faculty Publications

Disclosed is an electromagnetic beam directing means for use with sample analysis systems, such as relfectometers, ellipsometers and polarimeters and the like, use of which facilitates investigation of sample systems which are not mounted to a sample analysis system sample system supporting stage. The present invention eliminates the requirement os extensice sample analysis system component realignment when alternatingly performing analysis of sample systems mounted upon, and mounted other than upon, a sample analysis system sample system supporting stage.

A Multithreaded Scheduler For A High-Speed Simulator, Gene Saghi, Kirk Reinholtz, Paul Savory

Department of Industrial and Management Systems Engineering: Faculty Publications

The Cassini spacecraft is on its journey to Saturn to perform a close-up study of the Saturnian system; its rings, moons, magneto-sphere, and the planet itself. Sequences of commands will be sent to the spacecraft by ground personnel to control every aspect of the mission. To validate and verify these command sequences, a bit-level, high-speed simulator (HSS) has been developed. To maximize performance, the HSS is implemented with multiple threads and runs on a multiprocessor system. A key component of the HSS is the scheduler, which controls the execution of the simulator. The general framework of the scheduler can be …

A New Radiosonde System For Profiling The Lower Troposphere, Brian R Corner, Robert D. Palmer

Department of Electrical and Computer Engineering: Faculty Publications

A new, inexpensive radiosonde transmitter and receiver system has been developed for measuring wind field inhomogeneities in the planetary boundary layer using multiple simultaneously launched balloons. The radio- sondes use a narrowband-frequency-modulated carrier signal to transmit atmospheric pressure and temperature information to a surface receiver. The pressure and temperature data transmitted by the radiosondes allow their height above the surface to be ascertained. In addition, the radiosondes can be tracked with a photographic camera system to provide the azimuth and elevation angles of the radiosondes during their ascent, so that their three-dimensional horizontal position can be determined. By tracking the …

Ds Cdma Scheme For Watm Lan With Error Control, Beata J. Wysocki, Tadeusz A. Wysocki, Hans J. Zepernick

Department of Electrical and Computer Engineering: Faculty Publications (to 2015)

In the paper, we present simulation results for the 13 channel DS CDMA WATM LAN utilising optimized complex spreading signatures based on Walsh- Rademacber functions. The method to obtain those optimized spreading signatures, as well as the full set of the coefficients giving the minimum level of crosscorrelation between any pair of the channels is shown. The resultant system BER as well as the distribution of errors within WATM cells is given. The obtained results indicate that with the application of a hybrid ARQ scheme, capable of correcting 10 errors, the number of WATM cells which would require retransmission is …

Error Performance Of The 13-Channel Ds Cdma Watm Lan, Beata J. Wysocki, Tadeusz Wysocki, Hans J. Zepernick

Department of Electrical and Computer Engineering: Faculty Publications (to 2015)

In the paper, we present simulation results for the 13 channel DS CDMA WATM LAN utilising optimized complex spreading signatures based on Walsh-Rademacher functions. The method to obtain those optimized spreading signatures, as well as the full set of the coefficients giving the minimum level of cross-correlation between any pair of the channels is shown. The resultant system BER and the distribution of errors within encapsulated WATM cells is given. The obtained results indicate that with the application of a hybrid ARQ scheme, capable of correcting 10 errors, the number of WATM cells which would require retransmission is in the …

Agent Jurisprudence, Michael N. Huhns, Munindar P. Singh

Faculty Publications

The agent metaphor comes packaged with a number of powerful abstractions. Some of these are psychological, such as beliefs, knowledge, and intentions-abstractions that were traditionally studied in AI. However, there are a number of other abstractions that the agent metaphor brings to the fore. Of these, one has been emphasizing the social abstractions. Close cousins of the social abstractions are the ethical and legal abstractions. These too are being recognized as increasingly important in developing agents that are not only sociable, but also well behaved.

Digital Receivers, George Rofa

Theses : Honours

No abstract provided.

Study Of Electronic Cash: Its Impact On The Economy And Society, And Its Future, Sanjana Prasad

LLM Theses and Essays

Technological advancement has introduced an electronic method for the payment for goods and services. With these advancements and the growth of the internet, the market-place of the world has become one universe without borders. This paper examines the various methods of electronic payment for goods and services and the domestic and international laws that govern their operations. The paper explores concerns about money laundering, counterfeiting, internet security, cyber scams in electronic cash as well as proffered security solutions to these problems. The paper concludes with the proposition that electronic cash in the form of cards (ATM) are more accessible to …

Proposed Model Rules Governing The Admissibility Of Computer-Generated Evidence, Lynn Mclain, James E. Carbine

All Faculty Scholarship

Pursuant to a grant from the State Justice Institute, the Court of Appeals of Maryland Standing Committee on Rules of Practice and Procedure drafted, and the Court of Appeals adopted, model rules regarding computer-generated animations and simulations. The rules address discovery, pretrial rulings, and preservation of the record for appeal.

Congestion Control In Multicast Transport Protocols, Rajib Ghosh, George Varghese

All Computer Science and Engineering Research

We discuss congestion control mechanisms in multicast transport protocols and we propose TCP-M - a TCP-friendly Multicast transport protocol. TCP-M uses IP multicast to deliver data packets and acknowledgements to provide reliability. Ack implosion at the source is prevented by fusing acknowledgements at some intermediate routers. TCP-M reacts to network congestion exactly like TCP by having the sender emulate a TCP sender.